Increasing barley production in the face of declining soil fertility on smallholder farms is a critical challenge in Ethiopia. The objectives of this study were to (1) determine the optimum rates of nitrogen (N), phosphorus (P), potassium (K), and sulfur (S) fertilizers under a balanced fertilization of other macro- and micronutrients (zinc and boron) and (2) quantify the agronomic efficiency of N and P on Cambisols and Vertisols. The trials were conducted for three consecutive years (2014–2016) on farmers’ fields on 83 sites under rain-fed conditions. On each farm, six rates of N, P, K, and S with a balanced application of the other nutrients were laid out separately in a randomized block design with three replicates. Balanced fertilization resulted in yield increments of 26–59% on Cambisols and 18–74% on Vertisols, as compared with the control (0 N). Application of P increased grain yield from 11% to 30% and from 7% to 14% due to the interaction of P by soil type as compared with the control. The application of K and S, however, had no significant effect on barley yields on either soil type. The highest agronomic efficiency of N (AEN) was obtained from 46 kg N ha−1, with AEN increasing by 117% on Cambisols and 33% on Vertisols, as compared with the highest N rate of 230 kg N ha−1. The maximum agronomic efficiency of P (AEP) was recorded with 10 kg P ha−1 on Vertisols, with AEP increasing by 73% on Cambisols and 452% on Vertisols, as compared with the application of 50 kg P ha−1. With balanced application of other nutrients, use of 230 kg N and 20 kg P ha−1 was recommended for tepid sub-moist mid-highlands and Vertisols. For tepid sub-humid mid-highlands, application of 46 kg N and 20 kg P ha−1 with balanced application of other nutrients was recommended. For Cambisols, application of 230 kg N and 40 kg P ha−1 was recommended with balanced application of the other nutrients. Similarly, application of 230 kg N, 40 kg P, and 10 kg S ha−1 was tentatively recommended for cool sub-most mid highlands. However, response to K was inconsistent and therefore a firm recommendation could not be proposed for the study sites. Further research needs to be conducted on more soil types and locations.

Two bean genotypes differed in rate of root extension and elongation when grown under different soil water stresses in transparent tubes placed at an angle of 25°. Root intensity (the root length visible cm−2 of the viewing surface) gave a quick indication of the distribution of the total root length when screening cultivars for drought resistance.

There is no one widely accepted method of managing international agricultural research and numerous different models exist. Here we review one in particular, referred to as the ‘institute without walls’, from the perspective of the UK Department for International Development's (DFID) Renewable Natural Resource (RNR) Research Strategy (1990–2006). We begin with a brief history of the RNR Research Strategy from 1990 to 2004. We then draw on nearly 15 years experience of managing one of the programmes within the RNR Research Strategy to assess critically the impact of externally and internally imposed organizational and management changes on the performance of the DFID Plant Sciences Programme (PSP). The current RNR Research Strategy (1995–2006), with its emphasis on demand-led research, has greatly increased the relevance and effectiveness of DFID's natural resources research. A comparison between the PSP in 2004 and the early 1990s inevitably concludes that the programme has been transformed: unlike in 1991, research is now firmly demand-driven, much is based in developing countries and farmers are benefiting from the research. Over time, the outputs of the long-term strategic research have been applied in practical plant breeding and participatory crop improvement programmes. Key to the success of the PSP has been the provision of continuous, long-term funding which has allowed projects time to develop and produce outputs of real value to end users. Alongside this, the ability of the PSP to build long-term, in-country partnerships has ensured the effective adoption of its research outputs. We conclude that the successes of the PSP have largely derived from (i) identification of research that is clearly demand driven, (ii) continuous long-term funding that has allowed research to move from the strategic to adaptive phase, (iii) continuity of management, and (iv) the flexibility to develop a wide range of partnerships, both in-country and overseas, based on their ability to deliver.

A common practice in some South American countries consists in moving around Capsicum chinense cultivars between regions where edaphoclimatic conditions differ notably. The purpose of this research was to compare and relate gas exchange responses with assimilate allocation patterns and flower and fruit production dynamics in a cultivar of C. chinense in three locations with different mean temperatures (19, 24 and 28 °C) along a gradient from 140–1855 m. Leaf gas exchange (leaf conductance, CO2 assimilation and transpiration rates) was measured at 60–70, 110–120 and 140–150 days after transplanting (dat) from seed beds. Dry weight per plant of leaves, stems and roots were determined at 50, 73, 96, 114 and 196 dat. Flowering dynamics and fruit production were followed weekly. A marked reduction (50%) in mean Gs was found at the site with the lowest mean temperature in relation to plants grown at the highest temperature site. Mean daily CO2 assimilation rate was higher for plants in the intermediate site and a reduction of 18 and 42% was found for sites with highest and lowest mean temperature, respectively. We report an adverse effect of low temperatures on growth of C. chinense. Flowering initiation and fruit production was delayed at lower temperatures. An increase in temperature (between 26–30 °C) led to an increase in the number of flowers; below this temperature it remained unchanged. Fruit production is drastically reduced at the lower temperature site due to a large number of aborted flowers and small fruits.

In spite of large year-to-year variations in clove yields, production in the islands of Zanzibar and Pemba is often in synchrony and the annual harvests of the two islands are correlated with similar variables. Clove harvests are positively correlated with rainfall in October to February two years before the harvest and negatively correlated with the harvest in the previous year and rainfall around July, and October to December of the year before the harvest. It is likely that rainfall in these periods affects vegetative growth of the clove tree and clove bud differentiation.

This study examined the economic, technical, and social feasibility of an improved groundnut production technology at the farmer's level vis-à-vis traditional practices. Improved practices are shown to be superior, but several economic and technical issues are raised.

The auxin-transport-inhibiting morphactin chlorflurenolmethylester (CFM; Methyl 2-chloro-9-hydroxyfluorene-9-carboxylate) breaks the dormancy of axillary buds in young coffee plants and produces orthotropic shoots. A concentration of CFM as low as 50 mg/litre induced an average of 24 orthotropic shoots per 6-month-old seedling. This approach could provide a fast and inexpensive method of vegetative propagation for raising disease-resistant cultivars if adult clones respond similarly to the seedlings used here and the treatment does not adversely affect the propagation of induced shoots.

Supplementary irrigation experiments were conducted on a Clansthal sand and a Windermere clay. Irrigation treatments were based on the application of 1 inch of water when the soil moisture deficit reached 2·5, 3·5, 4·5 and 5·5 in. in 7 ft of soil on the sand, and 1·00, 1·75, 2·50 and 3·25 in. in 2 ft of soil on the clay. Each experiment included a dryland control and soil moisture was estimated weekly in each plot with a neutron probe. The results showed that there were significant linear increases in yield with increasing quantities of water applied. The crops exploited soil moisture to a depth of 6 ft in the sand and 3 ft in the clay, even with the maximum water treatments. Under dryland conditions, on the sand the crop exploited soil moisture to the wilting point only in the surface foot of soil, but on the clay the crop extracted moisture held at tensions greater than 15 bars in the top 3 ft of soil. The conclusions are that, where available water for supplementary irrigation is limited, heavy soils should be irrigated in preference to sandy soils, and that the most efficient use of both rainfall and irrigation water is achieved when 1 cusec is used to irrigate about 200 acres.

In mountainous areas of Continental South East Asia, double cropping in the irrigable valleys and terraces is often promoted as a way to increase farmers’ income while alleviating the pressure of agriculture on fragile slopes. However, cold temperature and low global radiation may constrain this strategy. Lethally cold events may occur, and increases in crop cycle length may jeopardize the correct timing of the main rice crop, taking place in summer. The model PYE (potential yield estimator) simulating the impact of temperature and radiation on the development and yield of annual crops was adapted to account for the range of temperature occurring in the area under study. It was calibrated against experimental data for the three crops that are most often considered as spring crops in the irrigable land of the northern mountains of Vietnam: rice, soybean and maize. Then a virtual experiment was designed in order to simulate various scenarios combining crop species and sowing date with climatic data accounting for variability of climate across years, location and elevation. Completed with a sensitivity analysis, it allowed to define favourable ‘sowing windows’ for non-water limited environments, based on the three following criteria: high average yield, low incidence over years of lethally cold events and low incidence over years of delays in the maturity of the spring crop. The length of this sowing window varied greatly across the scenarios tested. The widest was obtained for the case of soybean whatever the location and elevation, which makes it the less risky of the tested options. The approach followed proved effective to identify favourable and unfavourable environments in order to help better targeting the policy in support to the introduction of a spring crop in the mountains of Vietnam.

A two-year study considered the effect of pod harvesting intervals of 3, 5, 7, 9, 11 or 20 weeks after pod set (WAPS) on the relationship between the physical condition of the pods, seed maturation and quality in fluted pumpkin (Telfairia occidentalis). Pod characteristics, such as the intensity of bloom wax on the pod and stiffness of the pod ridges, showed perfect linearity and correlation with the age of the pod, whereas changes in seed quality factors – germination, dry matter, oil and protein concentrations were curvilinearly associated with the time of pod harvest. Thus, seed quality factors increased steadily up to nine WAPS then declined. The point at nine WAPS defined as physiological maturity for fluted pumpkin seed and approximate visible indications of this point in the field were fairly stiff pod ridge condition and fading of bloom wax.

Phosphorus, followed by potassium, were the plant nutrients that most limited yields during the third decade of a long-term fertilizer experiment on groundnut, maize and cassava conducted on an Ultisol in Ghana. Application of sulphate of ammonia significantly decreased soil pH, thus reducing crop yields. Superphosphate or mulch applied alone consistently increased the yields of all three crops. Application of potash increased the yield of cassava throughout the cropping period, but the potash × mulch interaction depressed yields in two of the three cropping seasons. Use of crop rotation, grass mulch and fertilizer, including small amounts of lime, enabled crop yields and soil fertility to be maintained at a fairly high level under continuous cropping.

The growth of Amaranthus hybridus under different daylight intensities was assessed in terms of physical, morphological and biochemical parameters. Maximum growth in many respects was achieved at about 70% of full daylight. However, full daylight favoured chlorophyll stability and maximum accumulation of total dry matter, carbohydrate, chlorophyll and ascorbic acid. The leaf area ratio increased uniformly with decrease in light intensity. Ageing was accelerated by full daylight. Reduced light intensity reduced dry matter accumulation in the roots more than in the stems or leaves.

The polyphagous nature of the dark-headed rice stem borer, Chilotraea polychrysa (Meyr.), may contribute greatly to its ability to survive periods of food shortage when rice plants are scarce. Investigations on the preference and survival of C. polychrysa on seven selected hosts belonging to the Gramineae revealed that it oviposited on all the hosts tested, but showed a marked preference for its normal host, rice (Oryza sativa). Survival rates on rice and the alternate hosts did not differ significantly. The percentage of larvae surviving to the adult stage was generally low because of the high rate of mortality from larval to pupal stage, irrespective of host species. In rice, there was distinct ovipositional preference for plants at the maximum vegetative stage rather than for younger plants. The larval survival rate increased with the age of the host from 35 to 65 days, but dropped sharply when infestation occurred on plants 80 days old, by which time the inflorescence is beginning to emerge.

The establishment of leys for biomass production during the winter months could be an alternative feed resource of low cost for small ruminants in Mediterranean basin. For this purpose, an experiment was carried out with six plant species mixtures (PSM) that were cut up to seven times from seeding. The results showed that all the PSM had their highest growth at the 2nd cut with Festuca arundinacea, Lolium perenne, Dactylis glomerata, Trifolium repens (FLDT) being superior as the dry matter production concerns compared with the PSM that gave seven cuts. The crude protein and the ether extracts contents in all the PSM decreased from the 1st to the last cut, while that of NDF and ADF increased. The concentrations of myristic, palmitic, stearic, oleic and linoleic acid increased in all the PSMs from the 2nd to the 5th cut, while the opposite was observed for the α-linolenic acid content. The concentration of α-linolenic acid was higher in the FLDT PSM when compared to others during all cuts. Taking into account all the examined parameters together, the FLDT seems to be superior to the other PSMs as animal feed for small ruminants, particularly during the period where there is no available grass from natural grasslands.

A uniformity trial was carried out at Banting, Selangor in West Malaysia to estimate optimal sampling rates for determining foliar nutrient contents of oil palms. The results suggest that the unit for sampling in this area is greater than 10 acres but less than 50. A comparison of the results with those obtained in Nigeria shows a large measure of agreement. Factors concerned in choosing a sampling rate are discussed. With the information available a rate of 2–3 per cent appears adequate.

In a three-year field experiment on acid peat (pH 3.47) up to 12 t/ha lime increased peat pH (0–30 cm depth) by 0.061/t. Annual guinea grass dry matter increased in quadratic relation with liming up to pH 4.20 (12 t/ha lime) but there was no difference between the cvs Sigor and Colonoa. Liming decreased the N, P and K, but increased the Ca and Mg contents of the harvested grass. Liming also increased the uptake of all five nutrients investigated, either linearly or curvilinearly.

A survey of citrus groves was conducted by analysing leaf and soil samples from the main citrus growing areas of the island. The leaf data, evaluated by comparing them with the California leaf analysis standards for assessing the nutrient status of citrus leaves, indicated that the California standards are of limited value in attempting to assess the nutritional status of citrus in Trinidad, particularly with reference to the elements zinc and magnesium. The possibility of using soil analyses as an index to the mineral nutrition of citrus is worthy of consideration. Although symptoms of zinc and magnesium deficiencies had often been observed, these elements had not been given the attention they deserved in the regular fertilizer programmes.

The changes taking place in the mixed farming systems of northwest Syria were examined by re-visiting, in 1996 and 2000, five villages along a rainfall gradient. The villages had been surveyed first in 1977–79. In those villages with moderate rainfall, intensification of crop production, namely a trend towards cereal monoculture and the planting of tree crops, did not lead to specialization in cropping at the expense of sheep ownership. In contrast, households in the areas too dry for most rainfed crops except barley (Hordeum vulgare) were more likely to sell their sheep because they depended heavily on off-farm income. Increases in crop yields were found but these only benefited the families in villages in the higher rainfall zones. Conversely, with the exception of ewe fertility, there was little evidence of improvements in sheep productivity. The mixed farming systems in the five villages sampled are still passing through a period of transition, and the cropping component will undoubtedly continue to change. This is less likely to happen to the small ruminant component in the near future unless the sector is given higher priority in national policy. As a strategy to increase feed production and balance the crop rotations, the prospects for closer crop/livestock integration at the farm level are limited by the many difficulties associated with the introduction of leguminous pasture and forage crops.